Preheat oven to 325 degrees F (165 degrees C). Grease an 8 inch springform pan. In a medium bowl, combine cookie crumbs and butter. Mix well and press into the bottom of springform pan.,In the top of a double boiler, heat chocolate, stirring occasionally, until chocolate is melted and smooth. Remove from heat and allow to cool to lukewarm.,______,Bake in the preheated oven for 60 minutes, or until filling is set. Allow to cool to room temperature, then refrigerate at least 4 hours before serving.